Sauté onions in coconut oil on medium low heat in preheated skillet until they begin to brown. Add garlic to onions after five minutes. Prepare zucchini and tomatoes while onions cook. Remove onions from skillet. Add more coconut oil. Sauté zucchini, oregano, parsley, and black pepper. Add tomatoes when zucchini almost cooked. Layer onions on top of zucchini tomato mix. Mix Panko crumbs and cheeses in a small bowl. Sprinkle over vegetables. Add more cheese if desired. Cover and cook on low heat until cheese is melted.